Re: Some comments on Boost.Jam and Boost.Build

From: jurko_jamboost (jurko_jamboost_at_[hidden])
Date: 2003-09-01 04:36:46

 Hi Volodya,

--- In jamboost_at_[hidden], Vladimir Prus <ghost_at_c...> wrote:
> I wonder, though, if we should issue an error if there are 
> several --build-system switches?

I guess that would have to be a more general coding-standard
decision. Are there any coding standards established for this
project that relate to this? In general do you disallow multiple
options or take the last one as valid. I see pros and cons for
eather of these choices but nothing too important. I guess the most
important thing would be to get it standardized and consistent
across the system. Ofcourse any special switches that apsolutely
need to be handled differently can easily be made to deviate from
the standard (well, a simple comment would be useful too :-) ).

> > 7. The IMPORT built-in rule is used in kernel/modules.jam with an
> > extra fifth parameter LOCALIZE which I can not find documented
> > anywhere and I have no idea what it does. Any hints?
> 
> The rule which is localized will access variables from the module 
to which 
> it's imported. I've attaches a small example to illustrate the 
different, 
> which can be run with
> 
> bjam -flocalization.jam
> 
> This was undocumented for some time already, unfortunately.

Ok, thanks! I get it now, but that one really needs documenting.
:-) I played with it a bit and gathered that the value of this
fifth parameter is not important but only its existance. That is,
if any value is passed as the fifth parameter then the new
localization behaviour is triggered. Is this correct? Or are there
any 'special' values that can modify this behaviour further?

> > 8. A funny side effect of the help system. If you do
> > bjam --help --help
> > the help screen is displayed twice :-))
> 
> Funny... but how to fix it. For example, should
> 
> bjam --help doc --help doc
> 
> produce help on "doc" twice, or not ;-)

My bet would be on not. The help options already affect all of the
help actions - whether triggered by parameters before setting those
options or after. So I guess all the help parameteres should be
processed first and only then should all the needed actions be
triggered. But whether this behaviour can be implemented at all
using the current parameter processing system - I can not tell. I
can look into it later if you wish.

HTH,
Jurko